Kim Yong-Bum, Garbisu Carlos, Pickering Ingrid J, Prince Roger C, George Graham N, Cho Myeong-Je, Wong Joshua H, Buchanan Bob B
Department of Plant and Microbial Biology, University of California, 111 Koshland Hall, Berkeley, CA 94720, USA.
Planta. 2003 Dec;218(2):186-91. doi: 10.1007/s00425-003-1102-8. Epub 2003 Sep 17.
The uptake, distribution and metabolism of selenite were examined in germinating homozygous barley ( Hordeum vulgare L.) grain with thioredoxin h overexpressed in starchy endosperm. Results were related to the null segregant in which the transgene had segregated out during crossing. Compared with the null segregant, the homozygote showed enhanced germination and root and shoot growth in the presence of 1 and 2 mM sodium selenite. The rate of incorporation of selenite by the homozygote was approximately twice that of the null segregant. Based on X-ray absorption spectroscopy, the major products in both cases were selenomethionine-like species and the red, monoclinic form of elemental selenium, a derivative not previously reported in green plants. Selenite and selenate made up the balance. The distribution of the products formed differed as to the tissue - root, shoot, aleurone, endosperm - but the ratios were similar in the homozygote and null segregant. The results provide evidence that, in addition to the accelerated germination observed previously in water, barley grain overexpressing thioredoxin h are resistant to the inhibitory effects of selenite. These properties raise the possibility that plants overexpressing thioredoxin h could find application in the remediation of polluted environments.
在淀粉胚乳中过表达硫氧还蛋白h的纯合大麦（Hordeum vulgare L.）发芽籽粒中，研究了亚硒酸盐的吸收、分布和代谢情况。研究结果与在杂交过程中转基因已分离出去的无效分离株相关。与无效分离株相比，在存在1 mM和2 mM亚硒酸钠的情况下，纯合子表现出发芽率提高以及根和芽生长加快。纯合子对亚硒酸盐的吸收速率约为无效分离株的两倍。基于X射线吸收光谱分析，在这两种情况下的主要产物都是硒代蛋氨酸类物质以及红色单斜晶型的元素硒，这是一种此前未在绿色植物中报道过的衍生物。其余部分由亚硒酸盐和硒酸盐组成。所形成产物在根、芽、糊粉层、胚乳等组织中的分布有所不同，但纯合子和无效分离株中的比例相似。这些结果提供了证据，表明除了之前在水中观察到的加速发芽外，过表达硫氧还蛋白h的大麦籽粒对亚硒酸盐的抑制作用具有抗性。这些特性增加了过表达硫氧还蛋白h的植物可应用于污染环境修复的可能性。
